The objective of this project is to investigate the growth differentiation factors in cartilage and bone. The research projects currently under study are: 1) purification of osteogenins from bovine and human bone; 2) actions of growth factors on bone differentiation in vivo; 3) compartmentation of transforming growth factor beta in bone; 4) expression of TGF beta during cartilage and bone development; 5) influence of human and rat tooth matrix on bone induction; 6) role of insulin-like growth factors and other differentiation factors in cartilage repair, and 7) role of osteogenin and other growth factors on chondrocytes and dedifferentiated chondrocytes in vivo.